The Reason Why
by quinnovative
Summary: Prompt: Lena takes a Kryptonite bullet for Kara, Kara tries to break up with her when she's healed because she thinks it's too dangerous for them to be together- Lena does not take this well. (Established Supercorp)
1. Chapter 1

**A/N:** This prompt came from AO3 and I hope you enjoy it! Also, if you're coming over from my story 'By Your Side,' I know I haven't updated in a while, but I'm working on it! Thanks for reading, I'd love to hear your thoughts. :)

* * *

Her only source of light are moonbeams, and the clatter of battle has given way to eerie silence, and something hurts—burns across her fingertips. Her hands are pressed against Lena Luthor's abdomen and her hands are covered in blood. Thick crimson blood that floods forward and pushes out into Kara's trembling palms and the blood saturates Kara's skin and Lena's clothes. And the dark haired woman's name spills from Kara's lips like the blood from her body.

"Oh Rao, Lena," Kara whispers again. She removes a red-stained hand away to brush a sheen of sweat off Lena's forehead. "You're okay. It's okay," Kara murmurs to drooping eyes as she puts her hand back in place over the hole in Lena's skin.

"Why did you do that? Oh Rao, why, Lena?" Her throat constricts as she talks, whispers that Lena's okay. She'll be fine. She's doing great. Help is on the way.

Kara's gaze is stuck on the CEO—the blood, the pale facial features contorted in pain, and sharp gasps puffing from her lungs, the hand tightening around the blonde's wrist—when it should be skimming the room to confirm that the attackers are still unconscious after Supergirl shoved them across the room and into the floor after Lena dove in front of a Kryptonite bullet meant for Kara.

But they're still passed out and scattered on the office floor and blood is still pouring from Lena's pale skin. "Hey, Lena, I'm going to call Alex, okay? She's gonna be able to help." Kara's voice quivers and tears beg to fall but she bites her lip and swallows the swell of emotions.

"Don't be scared, love, if I…" Lena trails off and pauses. "Just know that it was worth it and these… these past few months together have been the best of my life and some of the only months I've…" she breaks off with a painful gasp, squirming beneath Kara's super strength.

"Just hang on, Lena, hang on. I can't lose you."

"Okay," Lena murmurs, voice breathy and eyes drooping closed to a burning pain in her stomach and the fumbled words Kara whispers to her sister over the phone.

They have to pull her off Lena when they arrive—all the DEO agents and medics. Kara's grip is so tight, that no amount of prying removes it and instead Alex is at her sister's side and it takes a complete minute of soft words for Kara to inch back enough for the medics to take Lena.

Kara stands slowly as Lena disappears around the corner in a flood of tactical gear and a stretcher. Alex steps closer to Kara and the blonde stumbles slightly into Alex's arms. Her fingers brush the agent's shirt and Kara lets out a sharp yelp. "What's wrong?" the brunette asks, leaning back to examine Kara. "Oh, Kara," she gasps softly. "Your hands." She wraps her palms around the younger woman swaying unsteadily with each moment.

" 's a kryptonite bullet," Kara mutters and still, she won't make eye contact with her sister. "It was meant for me. Lena's in pain because of me."

"No, Kara, that's not true," Alex says, voice warm as she tugs Kara closer.

But Kara shakes her head against Alex's shoulder. "Yes it is. It is, Alex." And her breath is shaky, her mind running a continual loop of Lena jumping in front of Kara and crumbling to the ground as deep red blossomed across the white fabric of her shirt. "This is my fault."

/

Lena's in surgery and Kara's stuck waiting. She closes her eyes and buries her head in her arms all pressed tight against her knees with her hands pushed against her ears. She focuses on the numbness boring through her chest in an attempt to block her senses from the surgery and the clatter of metal and she searches for Lena's heartbeat amongst the hum of the city and the DEO and every other human in the world. It's hard to find even though it's right in front of her.

She feels a gentle touch on her back and uncurls herself just enough to look up when she hears her sister say her name.

"Alex?" Kara asks softly as she blinks blearily, they'd been separated when Kara arrived at the DEO and Supergirl was sent for a medical check despite her protests while Alex interrogated the new additions to the DEO's prison cells.

"Hey," she says and steps forward to take one of Kara's hands into her own.

The blonde catches sight of Maggie beside Alex and straightens. "Maggie," she hiccups and feels words escaping her. It's so hard to talk with the chaos in her head.

"Hey, Kid," Maggie says, rubbing Kara's shoulder with her thumb. "You okay?" she asks just as Kara runs her free palm along her Supergirl skirt and her fingertips collide with sticky drying blood. Lena's blood.

Before Kara can respond, a sob bursts from her lips and suddenly her chest is heaving and her lungs gasp for breath in between the shudders that wrack her frame in the cold, plastic waiting room chair. Hot tears spring from her eyes and scorch her cheeks before splattering against the tile floor.

"Okay, it's okay," Alex says softly as she reaches out to tuck a strand of hair behind Kara's ear and brushes her wet cheek. At the contact, Kara lurches forward into Alex's arms and buries her face into her sister's shoulder, as tears and hot breath touch her skin. "Kara, she should be fine. I talked to the doctors on the way in and Lena's already out of surgery. She'll be awake soon."

The words only push another strangled sob from deep in Kara's chest and she grasps Alex tighter. Everything had been so terrifying—a jolt to her system as the startling realization descended upon Kara that she couldn't keep Lena safe, that she put Lena in danger. Alex holds Kara with one hand and runs the other through her blonde hair over and over again.

Maggie rubs circles across Kara's back and the blonde lets one hand slip from her hold on Alex to take the detective's open palm. Maggie curls her fingers around Kara's and the blonde grips back, her hurricane of sobs ebbing into small hiccups and sniffles until she leans away from Alex and Maggie, drags the back of her hand across her cheeks, wiping away silent tears still streaming across her skin.

A hole is burning in her heart and pain is radiating through each cell of her body and it's the kind of ache that no powers or solar lamps or medicine can take away. There will be no relief, no cure. But she can protect Lena, even if she can't protect herself. She will keep Lena safe even if it makes her feel hollow and jaded and hopeless.

Kara untangles herself from the two women in front of her and with one last quivering breath she pulls herself back together, lets a blank expression fall across her face. When she speaks her voice is empty. "I know what I need to do." Then she turns around and leaves, closes the distance to Lena's room.

/

It takes Kara two hours to gather the courage to do it. Two hours to confirm that Lena's okay and stable and that nothing permanent has occurred, except for a bit of scar tissue that will one day form. Two last hours to soak Lena in, to observe from afar the softness of her hands and hair and lips. The only contact she allows herself is a gentle grip around Lena's fingers. Kara doesn't worry about memorizing Lena's heartbeat or the sound of her breathing—she can listen to that even when they're apart and she keeps her distance. She will grant herself that small mercy.

She feels a little like she's drowning as she chokes out the words before she disappears. "I love you, and that's why I have to leave you."

The fabric of a red cape is swallowed by the night.

Lena cracks her eyes open.


	2. Chapter 2

_I have to leave you._ Kara's last five words run through Lena's head, sob already lodged in her throat at their implication as she blinks blearily and looks around the empty room and wonders why everyone who's ever meant anything to her always leaves. She keeps quiet as doctors suddenly flood the room. They touch her and move things and check blinking machines. It's chaotic for a few long moments before they shuffle out one by one and Lena's left alone again.

Not even five minutes pass though, before the door creaks open hesitantly. Lena steels herself, makes her features passive.

"Hey," Alex says, stepping into the room. Maggie eases the door closed behind them and greets Lena. "How are you feeling?"

She shrugs before she can process it and Alex sees the little quiver of Lena's lips. Years of living with Kara has made her aware of these things, of these moments when people are just barely holding themselves together.

"Hey, you're safe. It's okay now," Alex says and walks toward the side of Lena's bed. Lena's throat feels tight. _Nothing_ is okay.

"Thank you for what you did, risking your life for Kara was rash and brave and admirable and I can't thank you enough for the love you show my sister everyday."

Alex rubs Lena's shoulder with her thumb and suddenly Lena's a little kid again and the only touches she knows are cold and manipulative. Lena flinches under the hand Alex places against her, yanking herself to the side. She bites her lower lip, tastes blood at the sharp pressure.

"Lena," Alex says and her voice is so gentle that Lena feels guilt and embarrassment flush her cheeks. She hates that she's always like this, hates herself.

The CEO pulls her eyes away from the shaking hands she's trying to hide by clasping them together. She meets Alex's gaze and sees the same worried look reflecting in Maggie's eyes. "Are you okay?"

Lena gives a curt nod. "Fine, thank you," and it's a lie. It's a lie because beneath the thin hospital sheets her whole body is quivering and her chest is tight, her head is spinning, her breath shaky and her heart worse.

"Do you know where Kara is? She said she was going to visit you but we haven't seen her since."

Lena blinks away the tears brimming in her eyes. _Never let them see you cry_ , her mother always used to say. Lena didn't know who "them" had been, and how or when it had shifted to anyone, and everyone and the rest of the world so that she was so guarded and composed all the time it felt like she lived alone in this whole damned galaxy.

"She..." Lena takes a breath, squeezing her eyes tightly closed. When she opens them Alex and Maggie are still looking at her with some shared concern for both Lena and the blonde in question. "She left," Lena admits and immediately feels sick to her stomach, and the words taste like chalk in her mouth and soot in her throat and Lena Luthor does not want to be a part of this world anymore, with its gentle touches that never seem to find her and the reassurances that are ripped away and the promises that always shatter like the bones of a small creature in her hand. This world that decimates everything and has conditioned her to destroy whatever it misses on its long and aching path of pain.

"We're going to find her," Alex says.

Lena doesn't doubt that—no, the notion that fills her with dread is the thought of who she will be when Kara returns but refuses to penetrate the border of Lena's life. Of what will happen to the broken, wilting spirit that flickers inside her like dying embers in hurricanes.

/

"Kara, what the hell are you thinking?" Alex yells as she climbs off her motorcycle, her headlights illuminate the Super suit silhouette against the inky blank sky, speckled with stars. Kara doesn't turn around at first, just keeps staring in front of her at the glimmering city lights below. Her knees are tucked against her chest, arms hung around them.

"Kara!" Alex calls again as she pulls the keys out of her bike and crosses the dirt road to where her sister is sitting at the top of a small mountain overlooking National City.

Kara finally turns, hair swishing across her back and over her shoulder as she moves. Alex sees moonlight glint back at her through the moisture in Kara's eyes, sees silvery reflections in the tear tracks streaking her cheeks.

Alex immediately softens and drops crisscross beside her sister, their knees knocking slightly. "Wanna tell me what's going on?"

"I can't lose her," Kara murmurs voice high with tears, shaking her head as she speaks. She pulls at the grass in front her and gazes down.

"You don't have to," Alex says and tucks a piece of hair behind Kara's ear.

"She… she took a bullet for me, Alex, and that—that's not… it's not okay. It's not safe." Her voice wobbles in the still night air. "And I can't be responsible for more deaths. I can't keep having people die for me or because of me. It's not worth it. I'm not worth it."

"I would die for you an infinity of times," Alex says, because she knows it's true. "Because you _are_ worth it, because that's the kind of thing you do for someone you love; and I know it's scary, Kara, especially for you after everything you've been through."

Kara sniffles and uncurls her legs to make more contact with Alex. "I don't want to hurt her."

"I hate to tell you this, Kar, but you're hurting her right now."

"It's better though, in the long run."

"Are you really sure of that?" Alex asks and Kara finally looks up.

Her face falls as she shakes her head. "No."

"Come 'ere." Alex opens her arms, pulls Kara close enough that she can hear her heartbeat if she listens closely. "Love comes with risks. It hurts sometimes."

"I know," Kara says, tucking her head beneath Alex's chin. "I've known that since I was twelve years old."

Alex nods, nuzzling Kara closer. "You have."

"I just don't want that to happen again. I can't lose anyone else, Alex, I can't." Her shoulders rise and fall with each violent, warm breath against the brunette's collarbone and the salty tears that drip onto Alex's shirt. "It'd be too much, it's already too much."

It always came back to that one day on Krypton when her planet was destroyed and ash scattered through space like water splashed in a puddle, and everyone she'd known and loved was left behind with empty lungs and bodies returned to dust. That day, those people, the planet.

It always came back,

And there was nothing Alex could do in these moments to bring her sister back down to Earth and the grassy field and the arms wrapped around her. Nothing to do but hug her and hold her close and whisper and in some way share in that pain.

"I can't lose her," Kara murmurs after minutes have passed and her sobs are quelled. Her watery lips brush the fabric of Alex's shirt.

"Then go get her back, sis."

For the first time that night, Kara cracks a smile and a little bit of sunshine gleams through the teary storm on her face and the pain of her beating heart. The moon casts a shiny halo across Kara's blonde hair as she wipes her eyes. Alex runs a hand over Kara's head, pats her back gently, and shifts to stand.

"You need a ride to the DEO?" Alex asks as she brushes grass and dirt from her pants.

Kara shakes her head. "I'm going to fly over, I need to see her now. I can't wait."

Alex nods, reaching out to give Kara's hand a last squeeze before the blonde hovers in the air to Alex's parting words. "I'm proud of you."

/

Kara lingers outside the door to Lena's room in the DEO medical wing. She can hear the dark haired woman's heartbeat thundering in her head. She needs to enter before the courage banging in her chest fizzles out.

Kara yanks open the door with shaking hands. She stands in front of Lena, the Super suit ditched for jeans and a pale cable knit sweater, but her glasses are gone and her hair falls in loose waves mused by flying. She's in some sort of limbo between the two versions of Kara and perhaps this is her truest, most unguarded self.

Lena glances up, green meets blue and their gazes hold. Neither can pretend to ignore the tear tracks and red rimmed eyes.

"I can't lose you," Kara says in an exhale of stinging breath. Her words put cracks in the silence but still Lena is motionless, fingers frozen where they were twisting the edge of her sheet and her breath is hot in her chest and her gaze is intense.

"And I know it's selfish and greedy but I can't stop thinking about you or hearing your voice or listening to your heartbeat. I couldn't stop if I tried." Kara pulls her lip between her teeth. "but Lena, I don't want to. I don't want to live without you. I couldn't. I can't. And I know it's wrong, but-" Kara breaks off, pulling a breath into her lungs.

"Then why did you leave?" Lena's voice is barely a whisper in the air as she stares at her hands.

Kara shifts her weight and rubs her forehead. "Because I didn't want to hurt you, because I'm not safe. It's risky for you to be with me and that's not fair to you."

"Kara, it's my decision to make." Her words are steady again and as Kara struggles to control her breathing she wonders how this woman composes herself so quickly. It makes the blonde's heart hurt, but then Lena speaks again and everything falls apart. "And I-" A sob chokes its way through her throat and the appearance of composure is shattered. "I deserve to be happy n-no matter what l-life tells me and you're what m-makes me happy. You're the _only_ thing that makes me happy in this life of pain and suffering and loneliness that I've stumbled through for so long. So _please, please_ don't leave me."

" _Lena,"_ Kara's voice shakes and is heavy with tears. "Oh Rao, Lena." Kara shoves away her own tears with a fist, but they keep falling, hot and large. "I'm not going to leave. I promise. I promise I won't." She uses her super speed to snap the distance closed between them. After their three months together, Kara knows when Lena needs space and when she needs touch. Right now, the latter is so overwhelming Kara can't move quickly enough. She crawls into the bed and opens her arms, letting out a sigh as Lena turns and burrows against her.

Kara runs her hand over Lena's hair. "I didn't know," the reporter whispers. "I didn't know you were so sad all the time."

Lena shakes her head. "Not all the time." Her breath is warm against Kara's skin, her heart is beating a wild symphony. "I'm not sad when I'm with you."

Kara's breath catches in her throat and each string of words she can put together dies on her tongue, so she's silent as she hugs Lena closer and rubs circles across her back.

"We're gonna fix this," Kara says after a few moments pass. "We're going to fix everything."

"I believe you." Lena looks up and suddenly their lips are pressed together and it's soft and slow and their tears are mingling and mixing before splattering against the sheet. Their hands brush cheeks and gather bundles of silky long hair and wipe away tears.

When they break apart Kara fills the silence. "I'm sorry for leaving, I didn't mean to run. I just… I got scared. Doesn't it scare you sometimes, Lena?"

Lena pulls Kara's hand against her cheek, presses against its warmth before letting her head loll against Kara's chest. "Of course, love, but that's not enough for me to leave. If something scares me, that's how I know it's real, that's how I know it's important."

"Thank you for saving my life, Lena. Even though it was reckless and stupid, and I hope you never do it again."

"I would if I had to."

"I know." Kara tangles her hand in Lena's dark hair. "And that terrifies me."

Lena shrugs, beginning to droop sleepily against Kara and sinking deeper into her warm touch. "You've saved my life countless times before, and in more than just one way."

"Lena, I love you," Kara admits and runs a hand over Lena's back.

"Kara," Lena chokes out and her fingers shake a little and her breath trembles.

She can't remember the last time she said these words that she's thinking, but now they swell inside her and beg to spill out like some long suppressed breath or secret that screams in her chest and vibrates through every cell in her body and when they finally pour into her conscious she feels relief that is more than relief; she feels infinity and the universe and completeness. She feels complete, she feels _happy_.

So she says them out loud and everything feels right.

"Kara, I love you, too."

And then she falls asleep to synchronized breath and synchronized hearts and synchronized souls that radiate the promise of forever. That is the reason why. The reason she stays and the reason Kara doesn't leave, even though it's dangerous and reckless and unfair. Because of love.

Kara is Lena's reason and Lena is Kara's, and together, that is enough. They are enough.

That night, as Lena sleeps and mumbles through her dreams, she declares her love for Kara on seven separate occasions and every single time Kara is right there, holding Lena and whispering it back.


End file.
